Mini Veggie Pot Pies

• nonstick cooking spray, for greasing
• 3 sheets frozen puff pastry, thawed
• 2 tablespoons
  grapeseed oil
• 1 small yellow onion, diced
• ½ small celery root, peeled and diced
• 2 medium carrots, diced
• 1 large parsnips, peeled and diced
• 1 small sweet potato, peeled and diced
• ¼ cup
  all purpose flour (30 g)
• 2 cups
  vegetable stock (480 mL)
• 1 teaspoon
  dried thyme
• 2 ½ teaspoons
  kosher salt
• 1 teaspoon
  freshly ground black pepper
• 1 large egg, lightly beaten

Special Equipment

• round cutter, 4 in ( 10 cm)